Certain devices use disk drives with perpendicular magnetic recording media to store information. For example, disk drives can be found in many desktop computers, laptop computers, and data centers. Perpendicular magnetic recording media store information magnetically as bits. Bits store information by holding and maintaining a magnetization that is adjusted by a disk drive head. In order to store more information on a disk, bits are made smaller and packed closer together, thereby increasing the density of the bits. Therefore as the bit density increases, disk drives can store more information. However as bits become smaller and are packed closer together, the bits become increasingly susceptible to erasure, for example due to thermally activated magnetization reversal or adjacent track interference.